The RAAM's Shadow Add-on for Gears of War 3 has 9 achievements worth 175 gamerscore.
As RAAM, execute Minh 10 times in Versus MP (Standard or Casual).
Complete "RAAM's Shadow" in 4 player co-op in either Arcade or Standard mode.
Complete "RAAM's Shadow" in Arcade Campaign on any difficulty.
As Mauler, kill 10 Gears by reflecting their bullets using your shield.
Using the Loader, kill 10 Locust.
Using the Hammer of Dawn Command Center, kill 50 Locust.
Play 10 matches of Versus as a member of Zeta (Barrick, Tai, Minh, or Valera)(Standard or Casual).
Complete "RAAM's Shadow" in Standard Campaign on any difficulty.
As RAAM, kill 50 Gears using your Kryll.